Hi Danny,
you can use Bookeo to manage scheduling and reservations of your gym classes.
We charge a low, fixed monthly fee. Our most popular plan is $39.95/month.
You can integrate the plugin into your WordPress website, and it would look similar to our live demo http://www.yoga-bookeo-demos.com/book-now.html.
For the integration in WordPress, please see our tutorial here: http://help.bookeo.com/customer/en/portal/articles/347548
You can sign up for a 30 day free trial at signup.bookeo.com – no credit card needed. You will be able to fully test the system, as all features are enabled during the free trial.
